Understand the dangers of Coronavirus variants

Understand the dangers of Coronavirus variants
Understand the dangers of Coronavirus variants
Covid-19, the subject in 2021 are the variants of the virus, that is, new forms of it that continue to emerge and cause concern because of their high potential for transmission and the fear of what they can do to the immunizers already developed.

See the main doubts about the variants and what we know about them so far.

What are variants of the virus?

The coronavirus infects cells and hijacks them to produce new copies of it. In the process of increasing his army, he ends up making some copy mistakes, called mutations.

Any isolated form in the laboratory with one or more mutations that distinguish the virus from the ancestral form is identified as a new variant of the virus, according to virologist and professor at the Faculty of Veterinary Medicine and Zootechnics at USP Paulo Eduardo Brandão.

In practice, strain and variant are the same. Cepe is the term that refers to a single sample isolated in the laboratory, while variant is the term that refers to the virus isolated in a region (for example, the London outbreak was by a variant identified in several samples there).

During the pandemic, several variants of the Sars-CoV-2 coronavirus have already been identified.

And why do variants arise?

Often pointed out as the cause of the worsening of the pandemic in Brazil, in fact they are the result of uncontrolled and high circulation of people.

The more the virus circulates, the greater the chances of mutations appearing – some of which facilitate the entry of the virus into cells or prevent the action of neutralizing antibodies.

How are variants baptized?

Brandão states that, in order to avoid stigmas, names of the geographic region in which the lineage was discovered are no longer assigned. The official nomenclature uses a letter (indicating the ancestral lineage, such as “B” or “P”) and numbers (for example B.1.1). So that this text does not turn into an alphabet soup and confuse the reader, we will use the cities of origin in some cases.

The variants known so far that cause concern are B.1.1.7, identified in the United Kingdom, B.1.351, which emerged in South Africa, the two Brazilian strains, P.1, originally from Manaus and already dominant in at least six Brazilian states outside Amazonas, and P.2, of great circulation in Brazil and first identified in Rio de Janeiro, and two strains found in the United States, CAL.20C, in southern California, and B.1.526 , in New York.

The first variant to be described was that of the United Kingdom, based on the mass sequencing of samples of the virus, mainly from the Kent region, in south London. To date, it has been detected in 111 countries and is prevalent across Europe.

Are the variants more dangerous than the original coronavirus?

B.1.1.7 was already known to be 43% to 90% more transmissible. Recently, researchers at the universities of Exeter and Bristol have also found that it is 64% more lethal and can cause more severe forms of the disease.

A new study published in the journal Nature this Monday (15) also points out that this variant may be associated with an increased risk of death. The analysis was done with more than 2 million tests and 17,000 deaths in England between September 2020 (when the variant was identified) and February 2021.

The authors estimate a 61% higher risk of death with the British variant.

Regarding the potential risk to public health, South Africa’s variant B.1.351 has been of concern. Although there is still no data that associate this variant with the greater severity or lethality of the disease, the strain that emerged in the African country has a transmission potential up to 1.5 greater and is not stopped by antibodies that help control the original form of the virus, demonstrating that a previous infection does not prevent reinfection.

P.1, or Manaus variant, also shows greater transmissibility, although there is still no consensus on how much more transmissible it is – scientists speak from 2.2 to up to 6 times more.

In common with the South African variant, P.1 also has the E484K mutation, linked to the blocking of the action of neutralizing antibodies that help prevent the entry of the original virus into cells. Cases of reinfection have also been reported and cannot be ruled out.

There is still a lack of data on higher lethality or severity of the disease in individuals infected with this variant, but the impression of health professionals and researchers who study the virus is that this strain would be related to the highest number of deaths observed in those places with a high incidence of P .1 in 2021, such as Manaus and Araraquara.

Another variant also appeared in Brazil, called P.2, described first from a case of reinfection with this new variant. As it is still poorly studied, there is no data on its greater lethality or severity, but it has the same mutation present in variants B.1.351 and P.1, capable of blocking the action of antibodies that neutralize the ancestral form of the virus.

Can variants hinder vaccines?

The British variant does not appear to have a potential impact on the vaccines available against Covid-19.

The South African variant, when tested against the serum of individuals vaccinated with the Pfizer, Moderna and Oxford / AstraZeneca vaccines, significantly decreased the level of antibodies present in the blood. Since the action of antibodies is one of the immune response mechanisms, this variant could potentially reduce the effectiveness of vaccines, according to studies in South Africa with the vaccines from Novavax and Janssen, which had a reduction in the effectiveness of their immunizers (from 89.1% to 48.6%, in the case of Novavax, and from 72% to 64%, for Janssen) when tested in that country.

A study with the serum of individuals vaccinated with Pfizer and Moderna vaccines against the Manaus variant showed a reduction in neutralizing antibodies, although to a lesser extent than that observed with B.1.351. Janssen conducted tests in Latin America and found a reduction in the effectiveness of its vaccine in the region, although there is still no confirmation that this reduction would be linked to P.1.

Preliminary data not yet officially released for the Oxford / AstraZeneca and Coronavac vaccines indicate that these vaccines are effective against Manaus’ P.1.

The study of Pfizer and Moderna vaccines with serum from vaccinated individuals showed a reduction in antibodies when tested against the P.2 variant, but there is no concrete data on reduced efficacy. For the other vaccines, there is no data.

It is important to note that, even with the reduction in efficacy, vaccines still have the potential to reduce hospitalization and severity of the disease, and there were no deaths in the group of vaccinated individuals in the two studies, indicating protection against death. In addition, they protect against the ancestral strain of the virus and can still be good allies for the immunization of the population.

Are there worrying new variants emerging?

Recently, researchers from Rede Viruses, Rede Corona-ômica-BR and the National Laboratory for Scientific Computing, found a new variant, not yet characterized as a distinct lineage, in the country. Named N.9, this form comes from another part of the evolutionary tree of Sars-CoV-2, distinct from the one that originated P.1 and P.2, but it also has the E484K mutation, which reduces the action of neutralizing antibodies . The variant is still under investigation and is not, at the moment, a VOC.

In the USA, two new strains have been identified: the first, CAL.20C, was found in southern California and appears to be a combination of two different forms. With five mutations in the virus’ S protein, only one, L425R, leads to greater concern for being in a region that may affect the action of antibodies.

There is no information yet on its most lethal potential, but the Californian variant appears to be more transmissible. When tested with Pfizer and Moderna vaccines, there was a reduction in neutralizing antibodies from sera from vaccinated individuals, but nothing very expressive or that could indicate a decrease in efficacy. There is no data for the other vaccines in use.

Finally, researchers at Caltech and Columbia University found a new variant in the New York area, called B.1.526.

There is still insufficient data on this variant to assess its potential for transmission or severity, but there is evidence of a potential reduction in the action of neutralizing antibodies.

What can I do to protect myself from variants?

Care has been the same since the beginning of the pandemic: social distance, wearing masks and hand hygiene.

Can variants infect those who have had Covid-19?

Yes. When it was discovered and even now months later, variant B.1.1.7 (British) did not appear to be related to cases of reinfection, but rather to an outbreak of new cases identified in a more virulent way.

In the case of variants from South Africa and Manaus, places that were hit hard by the pandemic in early 2020, the emergence of new variants in places where high prevalence of the virus had been pointed out indicates a potential blocking of the action of antibodies that protect against ancestral form of the virus. The same was seen in New York, a city with a high level of contamination in 2020 and where a new variant appeared in mid-February this year.

The first case of reinfection with a new variant in Brazil was reported with P.2, in Salvador, after an initial infection with the ancestral strain of the virus. These observations are indicative of the potential for reinfection of the new variants.

Get the latest news delivered to your inbox

Follow us on social media networks

PREV Family recovering from covid and contracting dengue and chikungunya afterwards
NEXT Did you know that chocolate is good for the eyes?